BEIJING (AP) - Beijing's notoriously dirty air got cleaner
during last summer's Olympic Games, but the weather played a larger
role than the government's massive pollution control measures, a
new report says.
The first major study on air pollution during the Olympics found
that conditions in Beijing were far worse than at other recent
Olympics, even with the government's cleanup campaign. Particulate
levels often exceeded what the World Health Organization considers
The report was published Friday in the journal Environmental
Science and Technology, and funded by the National Science
Foundation in the U.S. and the National Science Foundation in
The Chinese government's plans to control air pollution for the
Olympics gave international researchers a unique opportunity to
observe a large-scale experiment. Scientists from Oregon State
University and Peking University looked at Beijing's worst air
pollutant - tiny dust particles known as particulate matter - over
an eight-week period before, during and after the games.
When Beijing won the bid for the Olympics in 2001, China poured
some $20 billion into "greening" the city, including doubling the
number of subway lines, retrofitting factories with cleaner
technology and building urban parks.
Beijing officials also imposed drastic cleanup measures just
before the games in mid-July, including pulling half the city's 3.3
million vehicles off the roads, halting most construction and
closing dozens of factories.
The study found that particulate air pollution decreased by
about one-third during the two-week Olympic period compared with
But further investigation suggested that the weather, such as
rainfall and strong winds from the north and northwest, played a
much larger factor in clearing the air.
Meteorological conditions accounted for 40 percent of the
variation in concentrations of coarser particulate matter, or PM
10, while pollution control measures accounted for only 16 percent,
the study said.
"It was a giant experiment and a noble effort. But in the end,
the extra added measures didn't help reduce PM concentration as
much as had been expected," said Staci Simonich, an associate
professor of chemistry and toxicology at Oregon State University
who worked on the study.
At the same time, the findings don't invalidate the government's
efforts, said Zhu Tong, professor at Peking University's College of
Environmental Sciences and Engineering, and a co-researcher on the
"We learned a lot about how air pollution forms in a mega-city
like Beijing, and how much pollution comes from which sources,"
The findings also showed that the weather ushered some air
pollution in to Beijing from industrial regions south of the
capital that were not subject to pollution curbs, including Hebei,
Shandong, and Shanxi. Those results indicated the difficulties in
trying to control pollution from a city level when air masses tend
to move regionally.
The level of particulate pollution that athletes faced in
Beijing was twice as bad as in Athens, three times worse than
Atlanta and 3.5 times higher than that of Sydney.
Levels of PM 10, the coarser particulate matter, exceeded levels
that the WHO considered safe about 81 percent of the time, while
concentrations of the smaller particulate pollution PM 2.5, which
can cause more serious health consequences, exceeded WHO guidelines
100 percent of the time.
However, there has been no evidence so far of any health
problems linked to the short-term exposure of athletes or
spectators during the Olympics, researchers noted.
Pollution expert Fang Ming, now retired from Hong Kong
University of Science and Technology, said the findings don't break
new ground in terms of understanding how air pollution works.
"Having said that, it is useful to know the effectiveness of
the huge 'green Olympic' effort to clean up the air in Beijing,"
he said in an e-mailed response.
Overall, the Olympic pollution control efforts were worthwhile
because "it demonstrated to the Chinese government that they need
to pay more attention to the environment and it is good for the
country. It also says that this is doable and the people have to be
a part of the effort," he said.